Apparently, I'm upgrading@ 2006/01/14
If you've got a 3GHz-plus single-core Pentium 4 (like my old machine) that's chugging along happily (unlike my old machine), or a similarly speedy Athlon, there is still, incredibly enough, little reason for most people to upgrade.
If you're into 3D games, then you might be pleased by a better video card, and maybe you'd go to PCIe just for that. You might also want more RAM or hard disk space - or just a new hard disk, if yours is approaching its use-by date.
But a CPU that was speedy three years ago is still perfectly acceptable today.
Three years took us from the 300MHz P-II to the 1.5GHz P4. That wasn't a very exciting processor compared with its P-III and Athlon peers, but you get the idea. It was a big darn change.
Over the last few years, though, the CPU makers just haven't been able to make their processors run a whole lot faster. They've edged the clock speeds up slowly, they've made new chips of various types - the Pentium M is a darn good piece of hardware - but they couldn't wring anything like the usual 18-monthly doubling out of the technology.
Hence, dual core chips. Intel and AMD want everybody to think they need them.
But most computer users don't need dual core, and indeed won't even notice the difference.
Don't believe the hype.